Arthropod pests and their management, natural enemies and flora visitors associated with castor (Ricinus communis), a biofuel plant: a review

Interest in bioenergetic crops, such as the castor oil plant Ricinus communis (Euphorbiaceae), for production of biodiesel has increased in recent years. In this paper, phytophagous arthropods, their natural enemies and floral visitors associated with this plant in the world are reviewed. Despite its insecticidal properties, arthropods have been reported feeding on R. communis plants. The arthropod pests of R. communis damage all parts of the plant, including the seeds, where some toxic compounds are even more concentrated. In the scientific databases, we found reports of 193 arthropods associated to R. communis in different parts of the world. This information obtained in the scientific databases was concentrated in a database and analyzed according to the coevolutive hypothesis, which allows us to predict that the greatest wealth and abundance of phytogenic arthropods is found in the center of origin by R. communis. According to this review, Achaea janata, Spodoptera litura, Edwardsiana flavescens, Liriomyza trifolii, L. sativae, Spilosoma obliqua, Cogenethes punctiferalis, Oxyrhachis taranda, and Helicoverpa armigera are the most devastating pests in Asia. In Africa, Agrotis ipsilon, S. exigua, Nezara viridula, Trialeurodes ricini, and Tetranychus urticae were mentioned as the most important. In Central and South-America, Phyllophaga sp., Agrietes sp., Erinnyis ello, N. viridula, Corythucha gossypii, Falconia antioquiana, and S. marima are reported as pests of economic importance. The most commonly reported natural enemies of some of these arthropod pests were species of Bacillus thuringiensis, B. cereus, B. popilliae, Trichogramma achaeae, T. chilonis, T. minutum, T. australicum, T. dendrolimi, T. pretiosum, T. evanescens, Microplitis rufiventris, M. maculipennis, M. ophiusae, Telenomus remus, T. proditor, Stethorus siphonulus and S. histrio. Apis mellifera is recorded as the main insect pollinator of R. communis. Pest management methods used against the arthropod pests of R. communis include biological, ethological, mechanical, cultural, genetic, and chemical control.

ADULT LONGEVITY, FECUNDITY, AND POPULATION GROWTH RATES FOR TRIALEURODES RICINI MISRA (HOMOPTERA: ALEYRODIDAE) AT DIFFERENT CONSTANT TEMPERATURES

Longevity and reproductive potential of adult males and females of Trialeurodes ricini Misra were determined under laboratory conditions at four constant temperatures (20, 25, 30, and 35 ± 1°C). The resulting data were used to calculate life tables and rates of increase at each temperature. Females of T. ricini oviposited means of 183, 224, 294, and 132 eggs at 20, 25, 30, and 35°C, respectively, and had a mean longevity of 38.52, 28.15, 15.78, and 10.11 days at the same four temperatures. The net reproductive rate was 49.92, 72.26, 111.08, and 38.44, and the daily intrinsic rate of increase was 0,05, 0.11, 0.18, and 0.15 at 20, 25, 30, and 35 °C, respectively. Generation times decreased from 69.88 to 24.92 days with increasing temperature. The results indicate that T. ricini can, in otherwise unlimited conditions, persist and increase in numbers within the range 20–35°C.

Parasitism of the castor whitefly, Trialeurodes ricini (Homoptera: Aleyrodidae) by Encarsia formosa (Hymenoptera: Aphelinidae): bionomics in relation to temperature

Selected life history characteristics of Encarsia formosa Gahan parasitizing the castor whitefly, Trialeurodes ricini (Misra) were studied at three constant temperatures (20, 25 and 30°C). Egg-to-adult developmental time decreased from 32 days at 20°C to 13 days at 30°C. An average of 241 day-degrees was required to complete development above the lower threshold temperature (12°C). Juvenile mortality was 34, 40 and 47% at 20, 25 and 30°C, respectively. Mean longevity of E. formosa ranged from 7.7 days at 20°C, to 2.6 days at 30°C. Mean total fecundity ranged from 18 to 36 eggs/female. Intrinsic rate of increase (rm) increased with temperature from 0.065/day at 20°C to 0.169/day at 30°C. Generation times decreased from 37 to 14.5 days with increasing temperature.